Various vehicles have developed a system for automatically inflating vehicle tires while in transit. Typically referred to as a Central Tire Inflation System (CTIS), the CTIS allows the vehicle driver to inflate or deflate the vehicle's tires to a higher or lower pressure respectively to accommodate a variety of vehicle loads, and road and traffic conditions. Control of the vehicle tire air pressure is provided by an air pressure controller that can be automatically adjusted or manually controlled in the cab by the vehicle's driver. The system provides an air compressor that is connected through the air pressure controller to the vehicle's front and rear tires. Rotary seal connections are provided at each wheel to permit flow of air from the air supply to the tires while the vehicle is in motion and the wheels are rotating.
There are, however, several drawbacks to some existing CTISs. For example, in the HUMMVEE, the tires cannot be inflated directly at the rim, but only through the existing CTIS via the "tank Valve" at the hub. Additionally, the CTIS cannot be disabled. Also, only "standard," or military issue rims or wheels can be used to ensure operability with the CITS.